glslideshow keeps showing the same image

[machrider]

Binary package hint: xscreensaver

Using Kubuntu 8.04, I'm unable to get glslideshow to show more than one image. It seems to have chosen one image and always shows that image, despite being pointed at a directory with several images in it.

I used xscreensaver-demo to configure the pictures directory.

I tried the hacks recommended here: http://ubuntuforums.org/showthread.php?t=212512

Duration and pan are set to the same value (10).

Doesn't matter what I do, glslideshow just shows a single image (and crossfades every 10 seconds as if it was actually changing images, but it's always the same one).

[machrider (machrider)]

Just figured out that changing my images directory in xscreensaver-demo to another path, then putting back the original path got it to rescan the directory and find the new files I had copied in. It must scan the directory once and cache the values somewhere? I don't see any kind of cache file in my home directory.

Now it is rotating between the five images in the directory, except... it shows the same image twice, every time. So it'll be a sequence like: 4, 4, 1, 1, 2, 2, 4, 4, ...

This is incredibly frustrating to try to work with. I'm not even sure I'm looking at the right config file, but it appears that this stuff lives in ~/.xscreensaver. That file says duration and pan are both 10, with fade as 2. I've tried many, many combinations of values and it still has this behavior of showing each image twice before switching to the next one.

This seems like an INCREDIBLY simple concept and I'm blown away how completely wrong it is. It would be better if this screensaver option didn't exist in Kubuntu, given how aggravating it is to use.

[Tormod Volden (tormodvolden)]

Thanks for your report. Is this still an issue in Ubuntu 8.10? Please attach your ~/.xscreensaver file.

[Jonathan Thomas (echidnaman)]

We are closing this bug report because it lacks the information we need to investigate the problem, as described in the previous comments. Please reopen it if you can give us the missing information, and don't hesitate to submit bug reports in the future. To reopen the bug report you can click on the current status, under the Status column, and change the Status back to "New". Thanks again!

[Will Bellman (wbellman)]

I ran into the same issue and I worked it out. I figured I'd post what I found to see if it helps.

There's really two issues and one was right in the man page for glslideshow. From the man page:
---
       -pan seconds
               How long each pan-and-zoom should last. Default 6 seconds.

               With the default settings of -pan 6 -duration 30, each image
               will be displayed five times (30/6), and then a new image will
               be loaded. If you want a new image to be loaded at each fade,
               then set -pan and -duration to the same value.
---

This is the exact behavior I was seeing and sounds like what the other users are describing... So I modified '/usr/share/applications/screensavers/glslideshow.desktop' and set both duration and pan to the same value and it appear to be doing the same thing...

However, what I found was that when I tested by going to "Lock Screen" it wasn't picking up the changes even though the screen saver preferences panel did (System->Preferences->Screensaver). (Using something that modifies the visual like '-fps' is helpful to see if changes are being picked up or not.) What I had to do was restart gdm after I modified the glslideshow.desktop file. The xscreensaver-demo tool seemed to introduce uncertainty... Especially since the interface provides sliders that don't show the exact set value, and as the man page states above unless duration and pan are set to the same value the "same image cycling" issue appears... So, I nuked the .xscreensaver file in my home dir and added the 'imageDirectory:' parameter by hand. Restarted GDM and everything works now.

Not really a bug, the system just does something different then what (some) users expect.

I hope this helps.

[Vasa Maximov (mcv-geek)]

My five cents: i discovered that the value of the "-pan" should always be smaller than or equal to "-duration". If "pan" is greater - images will not change during slideshow.

The easiest way to set the right values is:
- run xscreensaver-demo
- choose GLSlideshow plugin
- click Settings
- set "Crossfade duration" to the leftmost value (None) or to the very little fraction from the left
- click Ok.
Now, slideshow should work as expected.

Another way is to edit:
~/.xscreensaver
Find the string containing:
glslideshow -root
and add:
-pan 9 -duration 10
(or your comfortable values). Save file and run xscreensaver-demo

I think, the bug here is that the default values for this screensaver is invalid in xscreensaver-demo, and because of this - plugin won't run as expected. Steps to reproduce:
1. open ~/.xscreensaver with any editor
2. kill the string, containing "glslideshow -root"
3. save file
4. open xscreensaver-demo, select GLSlideshow plugin - default params will be loaded.
Result: preview pane shows only one constant image.
Expected: preview pane should display sequence of random images
5. click settings
6. set "Crossfade duration" to None
7. Click ok
Result: slide show runs as expected

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Brendan Grieve (brendan-grieve)]

I'll add my 2c as I decided to do a strace on the config.

For KDE the configuration file is: -
  ~/.kde/share/config/glslideshowrc

Simply updating it to have matching pan/duration fixes the "issue". No need to install xscreensaver.

[Brendan Grieve (brendan-grieve)]

Sorry for double post. I don't believe this is a bug and can safely be closed. I do recommend however that the default config have matching pan/duration as it will then behave as a normal user expects.